1. Field of the Invention
This invention relates to 12.alpha.-substituted pregna-1,4-diene-3,20-diones of the general formula (I) ##STR1## wherein R is a hydrogen atom, R.sup.1 CO or R.sup.2 SO.sub.2 where R.sup.1 is a hydrogen atom, an alkyl group which may optionally be substituted or an aryl group which may optionally be substituted and R.sup.2 is an alkyl group.
2. Description of the Prior Art
The 12.alpha.-substituted pregna-1,4-diene-3,20-diones of the general formula (I) as provided by the present invention are novel compounds not yet described in the literature but derived from 12.alpha.-hydroxypregna-1,4-dien-3-one-20-carbaldehyde, which is produced by allowing a specific microbe to act upon deoxycholic acid and/or a salt thereof, and can be used as intermediates for the synthesis of antiinflammatory corticoids represented by prednisone, prednisolone, etc.
The so-far known process for producing prednisone starts with deoxycholic acid and involves twenty-odd steps [L. F. Fieser and M. Fieser: Steroids, pages 634-647, Reinhold, 1959]. However, as the reagents required are expensive and the process is time-consuming, the process is not fully satisfactory for industrial application.
Some of the present inventors found a method of producing 12.alpha.-hydroxypregna-1,4-dien-3-one-20-carbaldehyde with high selectivity and in high yield which comprises cultivating, in a medium containing deoxycholic acid and/or a salt thereof, a microbe belonging to the genus Alcaligenes which is capable of producing 12.alpha.-hydroxypregna-1,4-dien-3-one-20-carbaldehyde by utilizing deoxycholic acid and/or a salt thereof as the substrate.